In recent years, an electronic instrument such as a portable game device may be provided with a touch panel (.e., a combination of a flat panel display (display device) and a pointing device) ,An electronic instrument may include a touch panel on the front side and a touch pad on the back side so that the user can perform a touch operation on the front side and the back side of the electronic instrument (see JP-A-2011-36424, for example).
When an electronic instrument includes a touch pad on the back side, information about an operation input (e.g., menu screen) is normally displayed on the display provided on the front side. The user can operate the touch panel provided on the front side while observing an object displayed on the screen as if to directly touch the object.
However, since the user cannot observe the position of a finger or the like that touches the touch pad provided on the back side, it is difficult for the user to operate the touch pad provided on the back side as compared with the touch panel provided on the front side.
A touch operation input method has been widely used that allows the user to input an action to the selected target by selecting the target by performing a touch operation, removing a finger or the like from the touch pad or touch panel (canceling the touch operation), and retouching the target. For example, the touch operation input method allows the user to select a menu button displayed on a menu screen by performing a touch operation, and display a submenu by performing a retouch operation.
When the user performs such an operation on the touch panel provided on the front side, the user easily operate the touch panel while observing the menu screen displayed on the touch panel. However, it is difficult for the user to determine the touch position when performing a touch operation on the touch pad provided on the back side since the user cannot observe the movement of the finger. Therefore, the touch position may be shifted when retouching the target selected by performing the touch operation. The user may be confused if the retouch operation performed by the user is not appropriately reflected in the game. The user may not be able to smoothly play the game (particularly a time-trial game), and may not be involved in the game if such a situation occurs.